Water Supply Outlook for Alberta

July 2002

Table 3b - Water Supply Forecast as of July 1, 2002 - Oldman River Basin (Natural Flows)

Volume Forecast for July 1 to September 30 Year to date
Locations Volume in dam3 Volume as a % of Average Probable Range as a % of Average Reasonable Minimum as % of Average Forecast Ranking (lowest to highest) Recorded March-June 2002 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 320,000** 132 97-169 66 70/84 152*** 82/84
Belly River 103,000* 124 102-181 73 68/84 159*** 84/84
Waterton River 264,000* 148 102-239 66 77/84 145*** 80/84
Oldman River near Brocket 398,000* 152 111-182 71 73/84 153*** 78/84
Oldman River at Lethbridge 1,122,000* 137 96-191 64 70/84 155*** 81/84

*NOTE: The forecast shown is the March to September 2002 forecast minus the recorded volume to date

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** - This value is the natural volume and includes the U.S. share
*** - Recorded 2002 natural volumes are preliminary and subject to change
Average is calculated for the period 1912 to 1995

NOTE: There is: a 50% chance that the actual natural flow will fall within the probable range given; a 25% chance that the actual flow will be less than the lower bound of the probable range given; and a 10% chance that the actual natural flow will be less than the reasonable minimum. Actual day to day streamflow conditions may vary throughout the season as a result of the effects of streamflow diversion and reservoir storage.

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